Beach Surveys and Biodiversity Study
In order to identify the location and abundancy of oysters along the rocky and sandy shoreline of City Island, the first step is to document existing oyster populations, which is conducted by CIOR volunteers who perform beach surveys at low tide on a monthly basis. The object is to identify living oysters attached or not attached to substrate, as well as dead oyster shells, and all are counted and measured.
In addition to surveying beaches, volunteers have monitored the range of biodiversity in the waters around City Island. During the summer of 2019, 25 mesh plastic bags filled with cured oyster shells (generously donated by Coastal Steward) and securely closed, were hung at five different locations, each one facing a different navigational direction and exposed to different water conditions and flow. Each cage was tied to a dock pole and suspended from the bottom but fully submerged at low tide. The different species they attracted, including oyster juveniles, were collected and analyzed. A wide range of species were counted, measured, and photographed—from invertebrates such as tunicates and bryozoans to larger vertebrates, including eels and blackfish, as well as oyster predators (mud crabs and oyster drills) and oyster toadfish, which feed on crabs and snails. In total, more than 900 animals comprising 33 different species, were counted and measured, enabling the establishment of a baseline for responses to restoration efforts at each location.
In order to identify suitable sites for the eventual depositing of shells and of reef restoration, divers explore the shoreline of City Island and nearby locations to evaluate bottom substrate conditions. Naturally existing hard-bottom surface structure represents an ideal settlement surface for oyster larvae dispersed in the water during the spawning season and should be protected by our restoration efforts in order to promote reef enhancement.
Water quality fluctuates throughout the season and depends on location. Using water-quality measurement instruments, CIOR is performing real-time and on-site measurements of basic water-quality parameters around City Island and will continue to do so at regular intervals. This data is being explored and will be added to information available from other measurement stations near City Island, such as the EPA-approved Harbor Water Quality stations, and the monitoring in Eastchester Bay by Save the Sound and the Maritime College of SUNY. In collaboration with Save the Sound, the opportunity and feasibility of continuous monitoring of basic water-quality parameters using mounted data loggers at the proposed deployment sites are being explored. Parameters being measured by CIOR include water temperature, acidity or alkalinity of the water (pH), salinity, dissolved oxygen, turbidity, and water current velocity and tidal flow.
Oyster Research Stations
Oyster Research Stations (ORS): The first steps in CIOR’s restoration efforts have begun in our partnering with the Billion Oyster Project to deploy these stations at four strategically placed locations around City Island. The ORS cages are filled with cured shell material that has been seeded with oyster spat and are then attached and hung off two docks and two moorings. CIOR members and eco-volunteers are now monitoring the growth and mortality of the oysters in the cages on a regular basis.